From a low-distortion 300 watt (900 watt peak) switching amplifier Grotto i delivers extremely articulate bass. MartinLogan's unique high-performance topology eliminates the need for exaggerated amplifier power ratings, transient-blurring ported or passive radiator enclosures common to so many subwoofers. A proprietary servo monitoring and control system ensures that the woofer output is dramatically free of distortion, resulting in a faithful replica of the audio input signal.

A robust connection and control system allows simultaneous connection of both 2-channel stereo music and multi-channel home theater—and allows each source to have individual crossover and level settings. LFE input effectively uses no low-pass filter, leaving crossover control to the processor. Left/right line level and speaker level inputs integrate six discrete audiophile grade low-pass filters between 30–80Hz allowing a different level and crossover point when playing back two channel music.

RCA output allows multiple Grotto i's to operate in serial. A unique 25Hz level control allows adjustment of system response by ±10dB to eliminate low-frequency build-up or suck-out at problematic bass frequencies common to most rooms. Proprietary ETC spikes couple the sub directly to the floor, minimizing lost energy and allowing tight, well defined bass.

Grotto i is available at MartinLogan ESL Series dealers including independent retailers and mass-market retailers such as Tweeter. Retailing $1,295